Phase I/II trial assessing bortezomib and melphalan combination therapy for the treatment of patients with relapsed or refractory multiple myeloma

An overview of the VISTA trial: newly diagnosed, untreated patients with multiple myeloma ineligible for stem cell transplantation

Multiple myeloma, a plasma cell neoplasm, is the second most common hematologic malignancy after non-Hodgkins lymphoma and is responsible for 2% of cancer deaths. Melphalan and prednisone (MP) has been the standard treatment in elderly patients for many decades. The VISTA study evaluated the effect of this combination with or without the first-in-class proteasome inhibitor bortezomib in newly diagnosed myeloma patients who were not candidates for autologous stem cell transplantation. Altogether 682 patients were enrolled and prospectively randomized in this trial. All patients received nine 6-week cycles of oral melphalan (9 mg/m2) and prednisone (60 mg/m2) on days 1–4, either alone or with bortezomib administered intravenously (1.3 mg/m2 on days 1, 4, 8, 11, 22, 25, 29 and 32 during the first four cycles and on days 1, 8, 22, 29 during remaining course of therapy). Median time to progression (the primary end point of the trial) was 24 months in the bortezomib-containing group compared with 16.6 months in the control group (p < 0.001). Response was evaluated in 337 patients receiving bortezomib compared with 331 patients in the control group who received MP alone; the percentages of partial response or better was 71 vs 35% (p < 0.001), with complete response seen in 30 vs 4%, respectively (p < 0.001). Median response duration in both groups was 19.9 versus 13.1 months, respectively. Median overall survival has not been reached in VMP group compared with 43 months in the MP group (p < 0.001), and this benefit is maintained after long term follow-up and subsequent antimyeloma therapies. Hematological adverse events (AEs) were similar in both groups, although patients in the bortezomib group experienced more frequent peripheral sensory neuropathy (including 13% grade 3, with less than 1% grade 4). Overall, the occurrence of grade 3 AEs was higher in patients receiving bortezomib (53 vs 44%, p = 0.02), but the risk of grade 4 AEs was identical (28 vs 27%). These results confirm the superiority of MP plus bortezomib combination over MP therapy in treatment-naive patients with newly diagnosed multiple myeloma who are ineligible for autologous stem cell transplantation.

Treatment options for relapsed and refractory multiple myeloma

Treatment options for patients with relapsed myeloma have benefited from the development of new targeted agents. The use of bortezomib, thalidomide, and lenalidomide have dramatically changed outcomes for patients with relapsed myeloma. New agents are also in development, on the basis of preclinical rationale, as well as combinations of conventional and novel agents. Together each of these treatment approaches are being tested in phase I, II, and III clinical trials, with the goal of prolonged duration of remission and, ultimately, improved overall survival.

Bortezomib as the first proteasome inhibitor anticancer drug: current status and future perspectives

Targeting the ubiquitin-proteasome pathway has emerged as a rational approach in the treatment of human cancer. Based on positive preclinical and clinical studies, bortezomib was subsequently approved for the clinical use as a front-line treatment for newly diagnosed multiple myeloma patients and for the treatment of relapsed/refractory multiple myeloma and mantle cell lymphoma, for which this drug has become the staple of treatment. The approval of bortezomib by the US Food and Drug Administration (FDA) represented a significant milestone as the first proteasome inhibitor to be implemented in the treatment of malignant disease. Bortezomib has shown a positive clinical benefit either alone or as a part of combination therapy to induce chemo-/radio-sensitization or overcome drug resistance. One of the major mechanisms of bortezomib associated with its anticancer activity is through upregulation of NOXA, which is a proapoptotic protein, and NOXA may interact with the anti-apoptotic proteins of Bcl-2 subfamily Bcl-X(L) and Bcl-2, and result in apoptotic cell death in malignant cells. Another important mechanism of bortezomib is through suppression of the NF-κB signaling pathway resulting in the down-regulation of its anti-apoptotic target genes. Although the majority of success achieved with bortezomib has been in hematological malignancies, its effect toward solid tumors has been less than encouraging. Additionally, the widespread clinical use of bortezomib continues to be hampered by the appearance of dose-limiting toxicities, drug-resistance and interference by some natural compounds. These findings could help guide physicians in refining the clinical use of bortezomib, and encourage basic scientists to generate next generation proteasome inhibitors that broaden the spectrum of efficacy and produce a more durable clinical response in cancer patients. Other desirable applications for the use of proteasome inhibitors include the development of inhibitors against specific E3 ligases, which act at an early step in the ubiquitin-proteasome pathway, and the discovery of less toxic and novel proteasome inhibitors from natural products and traditional medicines, which may provide more viable drug candidates for cancer chemoprevention and the treatment of cancer patients in the future.

Stem cell marker nestin is expressed in plasma cells of multiple myeloma patients

Nestin is considered to be a characteristic marker of multipotent proliferative precursors found in some embryonic and fetal tissues. Its expression might be a suitable diagnostic and prognostic indicator of malignancy and a potential marker of cancer stem cells in solid tumors. Unexpectedly, nestin protein was detected in mature CD138(+)CD38(+) plasma cells of multiple myeloma patients and statistical analysis confirmed significant differences between myeloma patients and control group without hematological malignancy. Our results represent the first evidence of nestin expression in multiple myeloma. Further studies are required to elucidate the role of this protein in multiple myeloma.

The efficacy and safety of bortezomib and dexamethasone as a maintenance therapy in patients with advanced multiple myeloma who are responsive to salvage bortezomib-containing regimens

BACKGROUND

Although treatment for multiple myeloma (MM) has considerably improved in the past decade, MM continues to be an incurable hematological malignancy that causes most patients to eventually relapse and die from their illness. Thus, the identification of effective salvage strategies remains a priority.

METHODS

In this trial, the authors evaluated the safety and efficacy of bortezomib and dexamethasone [V: on days 1 and 15 (1.3 mg/mq); D: on days 1-2 and 15-16, every 28-day cycle until progression (20 mg/d)] as maintenance therapy (MT) in patients with advanced MM who responded to salvage therapy that used a bortezomib-containing regimen.

RESULTS

Forty-nine MM patients were enrolled in this study between October of 2004 and April of 2008. All patients who were included in this study were responsive to a prior salvage therapy with bortezomib and had a measurable disease. The bortezomib and dexamethasone MT improved the quality of responses to complete remission in 4 patients and very good partial response in 3 patients. In addition, 10 patients experienced at least a 50% improvement in their symptoms. The median time to progression (TTP) was 16 months with a progression-free survival of 61% after 1 year. The overall response after 1 year was 76%, and the cumulative incidence of death due to disease progression, which was adjusted for competitive risk events, was 14%. Non-dose-limiting toxicities included neuropathy (predominantly grade 1), herpes zoster reactivation, pneumonia, and gastrointestinal affections (constipation and diarrhea). Three patients developed grade 2 neuropathy, which required a bortezomib dose reduction to 1.0 mg/mq. No grade 3 or 4 toxicities were recorded.

CONCLUSIONS

The use of bortezomib and dexamethasone as MT in advanced MM was effective and well tolerated. The twice-monthly bortezomib infusion appeared to reduce the incidence of grade 3 and 4 neuropathies in comparison to similar experiences in other settings.

Treatment of relapsed and refractory multiple myeloma in the era of novel agents

The introduction of the Immunomodulatory drugs (IMiDs) and proteasome inhibitors, used either as a single-agent or combined with classic anti-myeloma therapies, has improved the outcome for patients with relapsed myeloma. However, there is currently no generally accepted standard treatment for relapsed/refractory myeloma patients, partly because of the absence of trials comparing the efficacy of the novel agents in relapsed/refractory myeloma. Choice of a new treatment regimen depends on both patient and disease-specific characteristics. A lenalidomide-based regimen is the first choice in patients with neuropathy, while bortezomib has the highest efficacy in patients with renal insufficiency and is not associated with increased risk of thromboembolism. A second autologous stem cell transplantation (auto-SCT) can be applied in patients with a progression-free period of ≥ 18-24 months after the first auto-SCT. In high-risk relapse such as occurring early after auto-SCT consolidation with allogeneic SCT can be considered. In this review we provide an overview of the various salvage regimens and give recommendations for treatment of patients with relapsed/refractory myeloma in different clinical settings.

A phase I study of bortezomib in combination with doxorubicin and intermediate-dose dexamethasone (iPAD therapy) for relapsed or refractory multiple myeloma

Bortezomib and doxorubicin have synergistic activity against myeloma cells in vitro. We underwent a dose finding study of bortezomib in combination with a fixed dose of doxorubicin and intermediate-dose dexamethasone (iPAD therapy) in patients with relapsed or refractory myeloma. Bortezomib was administered on days 1, 4, 8 and 11 at a dose of 1.0 and 1.3 mg/m² in cohorts 1 and 2, respectively. Doxorubicin 9 mg/m² was given by rapid intravenous infusion on days 1-4, and dexamethasone 20 mg on days 1-2, 4-5, 8-9 and 11-12. Treatment was repeated at a 3-week interval and the dose-limiting toxicity (DLT), defined as grade 4 hematological toxicity lasting more than 5 days and/or grade 3 or higher non-hematological toxicity, was evaluated. In cohort 1, 2 of 6 patients developed DLTs including grade 4 hyponatremia and grade 3 infection with appropriate neutrophil counts. No DLT was observed in the remaining 4 patients, indicating this dose was tolerable. In cohort 2, 3 of 5 patients developed DLTs including grade 4 thrombocytopenia lasting more than 5 days, grade 3 hepatic transaminase elevation and grade 3 ileus, indicating this dose was intolerable. It is concluded that bortezomib at the dose of 1.0 mg/m² is recommended in combination with doxorubicin and intermediate-dose dexamethasone.

Bortezomib and melphalan as a conditioning regimen for autologous stem cell transplantation in multiple myeloma

BACKGROUND

High-dose melphalan (200 mg/m(2)) with autologous stem cell transplantation (ASCT) is the standard treatment for young patients with multiple myeloma (MM). However, the response rates after ASCT are often unsatisfactory. We performed a pilot study by using bortezomib-melphalan as conditioning regimen for ASCT in Korean patients with MM.

METHODS

The conditioning regimen consisted of administration of intravenous infusion of bortezomib 1.0 mg/m(2) on days -4 and -1 and melphalan 50 mg/m(2) (day -4) and 150 mg/m(2) (day -1). In this study, we enrolled 6 newly diagnosed patients and 2 patients with relapse.

RESULTS

The disease status of the 6 newly diagnosed patients at ASCT was as follows: 1 complete remission (CR), 1 very good partial remission (VGPR), and 4 partial remissions (PRs). The disease status of the 2 relapsed patients at ASCT was PR. All patients except 1 showed adequate hematologic recovery after ASCT. The median time for the absolute neutrophil counts to increase over 500/mm(3) was 13 days (range, 10-19 days). Six patients with VGPR or PR at the time of transplantation showed an improvement in response to CR after ASCT. The patients were followed up without any maintenance treatment after ASCT except 1 patient who died during ASCT. During the follow-up period, CR was maintained in 3 newly diagnosed patients, but the other 4 patients, including 2 newly diagnosed patients, relapsed.

CONCLUSION

Conditioning regimen consisting of bortezomib and melphalan may be effective for ASCT in MM; however, the feasibility of this regimen should be further evaluated in large study populations.

The histone deacetylase inhibitor LBH589 enhances the anti-myeloma effects of chemotherapy in vitro and in vivo

Panobinostat (LBH589) is a potent histone deacetylase inhibitor (HDACi) that has shown anti-tumor activity in preclinical studies in both solid and hematological malignancies. We evaluated the anti-multiple myeloma (MM) effects of LBH589 alone and with melphalan or doxorubicin using MM cell lines and our human MM xenograft model LAGλ-1. LBH589 treatment resulted in increased acetylation of histones, induction of caspase cleavage, inhibition of cell proliferation and synergistic anti-MM effects with melphalan or doxorubicin in vitro. LBH589 with melphalan or doxorubicin also showed significantly enhanced anti-myeloma activity in vivo. These findings provide the basis for clinical development of these combination therapies.

Targeting the Fanconi anemia/BRCA pathway circumvents drug resistance in multiple myeloma

The Fanconi anemia/BRCA (FA/BRCA) DNA damage repair pathway plays a pivotal role in the cellular response to replicative stress induced by DNA alkylating agents and greatly influences drug response in cancer treatment. We recently reported that FA/BRCA genes are overexpressed and causative for drug resistance in human melphalan-resistant multiple myeloma cell lines. However, the transcriptional regulation of the FA/BRCA pathway is not understood. In this report, we describe for the first time a novel function of the NF-kappaB subunits, RelB/p50, as transcriptional activators of the FA/BRCA pathway. Specifically, our findings point to constitutive phosphorylation of IkappaB kinase alpha and subsequent alterations in FANCD2 expression and function as underlying events leading to melphalan resistance in repeatedly exposed multiple myeloma cells. Inhibiting NF-kappaB by small interfering RNA, blocking the IkappaB kinase complex with BMS-345541, or using the proteasome inhibitor bortezomib drastically reduced FA/BRCA gene expression and FANCD2 protein expression in myeloma cells, resulting in diminished DNA damage repair and enhanced melphalan sensitivity. Importantly, we also found that bortezomib decreases FA/BRCA gene expression in multiple myeloma patients. These results show for the first time that NF-kappaB transcriptionally regulates the FA/BRCA pathway and provide evidence for targeting Fanconi anemia-mediated DNA repair to enhance chemotherapeutic response and circumvent drug resistance in myeloma patients.

Bortezomib

The ubiquitin-mediated degradation of proteins in numerous cellular processes, such as turnover and quality control of proteins, cell cycle and apoptosis, transcription and cell signaling, immune response and antigen presentation, and inflammation and development makes the ubiquitin-proteosome systems a very interesting target for various therapeutic interventions. Proteosome inhibitors were first synthesized as tools to probe the function and specificity of this particle's proteolytic activities. Most synthetic inhibitors rely on a peptide base, which mimics a protein substrate, attached at a COOH terminal "warhead". Notable warheads include boronic acids, such as Bortezomib and epoxyketones, such as carfilzomib. A variety of natural products also inhibit the proteosome that are not peptide-based, most notably lactacystin, that is related to NPI-0052, or salinosporamide A, another inhibitor in clinical trials. The possibility that proteosome inhibitors could be drug candidates was considered after studies showed that they induced apoptosis in leukemic cell lines. The first proteasome inhibitor in clinical application, Bortezomib showed activity in non small cell lung and androgen-independent prostate carcinoma, as well as MM and mantle cell and follicular non-Hodgkin's lymphoma. It is now lincensed for the treatment of newly diagnosed as well as relapsed/progressive MM and has had a major impact on the improvement in the treatment of MM in the last few years.

Novel agents for relapsed and/or refractory multiple myeloma

The introduction of novel agents, such as thalidomide, bortezomib, and lenalidomide, has altered the landscape of therapeutic options for multiple myeloma by offering new mechanisms for targeting this disease. Combinations of these agents, with each other and/or traditional chemotherapeutics, have vastly increased the treatment options for patients both frontline, and at relapse, providing higher response rates, and importantly, increasing median overall survival. In this review, we will discuss the use of these novel agents and their combinations in patients with relapsed and/or refractory multiple myeloma.

The proteasome inhibitor CEP-18770 enhances the anti-myeloma activity of bortezomib and melphalan

The anti-multiple myeloma (MM) efficacy of bortezomib has led to the development of other proteasome inhibitors (PI), including CEP-18770 which has shown anti-MM effects in preclinical studies. However, the efficacy of orally (PO) or intravenously (IV) administered CEP-18770 in multiple MM models and in combination with conventional anti-MM therapies has not been evaluated. Herein, we show that CEP-18770 combined with melphalan or bortezomib induces synergistic inhibition of MM cell viability in vitro. In MM xenograft models, the addition of CEP-18770 IV to melphalan completely prevented the growth of both melphalan-sensitive and melphalan-resistant tumours. The combination of CEP-18770 IV and bortezomib induced complete regression of bortezomib-sensitive tumours and markedly delayed progression of bortezomib-resistant tumours compared to treatment with either agent alone. Single agent CEP-18770 PO also showed marked anti-MM effects in these xenograft models. These studies provide strong preclinical rationale for further development of this novel PI in the treatment of MM as a monotherapy as well as combined with either melphalan or bortezomib.

Bortezomib in combination with dexamethasone and subsequent thalidomide for newly-diagnosed multiple myeloma: a Chinese experience

OBJECTIVE

Bortezomib-dexamethasone-thalidomide has been reported to be effective in newly-diagnosed multiple myeloma (MM) with an overall response rate of 92% and a CR rate of 18% (Alexanian et al, Hematology 2007;12(3):235-9), but this regimen has not been tested in the Chinese patients. We report here our results testing with this combination in the Chinese population and to investigate the efficacy and safety of bortezomib in combination of dexamethasone plus subsequent thalidomide as primary treatment for MM.

METHODS

Between June 2006 and March 2008, 20 consecutive newly-diagnosed patients with symptomatic MM were treated with bortezomib at 1.3mg/m(2) IV on days 1, 4, 8 and 11 and dexamethasone at 20mg/m(2) IV daily on the day of bortezomib and the day after. All patients received daily oral thalidomide that was escalated from 100mg to 200mg. Fourteen patients were male and 6 were female. Median age was 59 years (range 43-86 years). 11 patients were stage 2 according to the International Staging System, 8 were stage 3, only 1 patient was stage 1. All patients received a median of two cycles of therapy (range 1-6). The EBMT criteria were used for response evaluation. Toxicities were evaluated according to the NCI Common Toxicity Criteria version 3.

RESULTS

16 out of 20 patients (80%) achieved PR and 3 (15%) achieved CR; therefore the overall response rate was 95%. With a median follow-up duration of 7.8 months (4-22 months), no patients died. Grade 3-4 toxicities included fatigue (3/20), thrombocytopenia (10/20) diarrhea (5/20) and orthostatic hypotension (3/20) Grade 2 neuropathy occurred in four out of 20 patients and herpes zoster occurred in four out of 20 patients. Routine anticoagulation or anti-thrombosis was not used. Only 1 patient suffered from DVT/PE.

CONCLUSIONS

Our preliminary experience in Chinese patients indicated that bortezomib-dexamethasone-thalidomide is highly effective in newly-diagnosed MM. Grade three and 4 toxicities are rare after median 2 cycles of therapy. The relative lower rates of neuropathy and DVT/PE in the Chinese patients with MM are being cautiously observed.

Bortezomib and high-dose melphalan as conditioning regimen before autologous stem cell transplantation in patients with de novo multiple myeloma: a phase 2 study of the Intergroupe Francophone du Myelome (IFM)

Autologous stem cell transplantation (ASCT) is recommended for younger patients with newly diagnosed multiple myeloma. Achieving complete response (CR) or at least very good partial response (VGPR) is a major prognostic factor for survival with 20% to 30% of patients achieving CR after ASCT. Bortezomib has shown synergistic effects with melphalan and no prolonged hematologic toxicity. In this Intergroupe Francophone du Myélome (IFM) phase 2 study, 54 untreated patients were enrolled between July and December 2007 to receive bortezomib (1 mg/m(2) x 4) and melphalan (200 mg/m(2)) as conditioning regimen (Bor-HDM). Overall, 70% of patients achieved at least VGPR, including 17 patients with CR (32%) after ASCT. No toxic deaths were observed. Bortezomib did not increase hematologic toxicity. Only 1 grade 3 to 4 peripheral neuropathy was reported. A matched control analysis was conducted comparing our cohort with patients from the IFM 2005-01 trial (HDM alone). Patients were matched for response to induction therapy and type of induction: CR was higher in the Bor-HDM group (35% vs 11%; P = .001), regardless of induction therapy. These results suggest that Bor-HDM is a safe and promising conditioning regimen. Randomized studies are needed to assess whether this conditioning regimen is superior to HDM alone. This trial was registered at www.clinicaltrials.gov as NCT00642395.

Proteasome inhibitors in the treatment of multiple myeloma

Targeting intracellular protein turnover by inhibiting the ubiquitin-proteasome pathway as a strategy for cancer therapy is a new addition to our chemotherapeutic armamentarium, and has seen its greatest successes against multiple myeloma. The first-in-class proteasome inhibitor, bortezomib, was initially approved for treatment of patients in the relapsed/refractory setting as a single agent, and was recently shown to induce even greater benefits as part of rationally designed combinations that overcome chemoresistance. Modulation of proteasome function is also a rational approach to achieve chemosensitization to other antimyeloma agents, and bortezomib has now been incorporated into the front-line setting. Bortezomib-based induction regimens are able to achieve higher overall response rates and response qualities than was the case with prior standards of care, and unlike these older approaches, maintain efficacy in patients with clinically and molecularly defined high-risk disease. Second-generation proteasome inhibitors with novel properties, such as NPI-0052 and carfilzomib, are entering the clinical arena, and showing evidence of antimyeloma activity. In this spotlight review, we provide an overview of the current state of the art use of bortezomib and other proteasome inhibitors against multiple myeloma, and highlight areas for future study that will further optimize our ability to benefit patients with this disease.

The ubiquitin-proteasome system in cancer, a major player in DNA repair. Part 2: transcriptional regulation

DNA repair is an indispensable part of a cell's defence system against the devastating effects of DNA-damaging conditions. The regulation of this function is a really demanding situation, particularly when the stressing factors persist for a long time. In such cases, the depletion of existing DNA repair proteins has to be compensated by the induction of the analogous gene products. In addition, the arrest of transcription, which is another result of many DNA-damaging agents, needs to be overcome through regulation of transcription-specific DNA repair pathways. The involvement of the ubiquitin-proteasome system (UPS) in cancer- and chemotherapy-related DNA-damage repair relevant to the above transcriptional modification mechanisms are illustrated in this review. Furthermore, the contribution of UPS to the regulation of localization and accessibility of DNA repair proteins to chromatin, in response to cellular stress is discussed.

A phase II evaluation of bortezomib in the treatment of recurrent platinum-sensitive ovarian or primary peritoneal cancer: a Gynecologic Oncology Group study

OBJECTIVE

To determine the activity and pharmacodynamics (PD) of bortezomib in platinum-sensitive epithelial ovarian or primary peritoneal cancer (EOC/PPC).

PATIENTS AND METHODS

Eligible women with recurrent EOC/PPC progressing between 6 and 12 months after initial chemotherapy were treated with bortezomib on days 1, 4, 8, and 11 [1.5 (cohort I) and 1.3 (cohort II) mg/m(2)/dose]. Patients must have had initial chemotherapy only. Response Evaluation Criteria in Solid Tumors (RECIST) was assessed by computed tomography (CT) scan every 2 cycles. 20S proteasome activity was quantified in three pre-treatment and a 1-hour post-treatment (cycle one, day 1) whole blood lysates.

RESULTS

Initially, 26 evaluable patients were treated at the 1.5 mg/m(2)/dose level. Objective response rate was 3.8% (1/26), a partial response. An additional 10 patients (38.5%) had stable disease. Given concerns that treatment discontinuations due to toxicity limited drug exposure/activity a second cohort of 29 evaluable patients was accrued at 1.3 mg/m(2)/dose. The 1.3 mg/m(2)/dose regimen is currently approved as an indication for multiple myeloma and mantle cell lymphoma. Treatment was more tolerable, although objective responses remained low at 6.9% (2/29, partial responses). Second stage accrual was not warranted at either dose. Bortezomib effectively inhibited 20S proteasome activity in whole blood lysates between 37 and 92% in 24/25 (96%) patients in cohort I, and 14-84% in 27/28 (96%) patients in cohort II who provided satisfactory pre- and post-treatment specimens for testing.

CONCLUSION

Bortezomib has minimal activity as a single-agent in the treatment of recurrent platinum-sensitive EOC/PPC. Treatment with bortezomib at 1.5 mg/m(2)/dose was not feasible in this patient population due to excess toxicity. Bortezomib was well tolerated at 1.3 mg/m(2)/dose.

Frontline treatment in elderly patients with multiple myeloma

Melphalan-prednisone-thalidomide (MPT) and melphalan-prednisone-bortezomib (MPV) currently appear to be the treatments of choice for a large proportion of elderly multiple myeloma (MM) patients ineligible for autologous stem cell transplantation (ASCT). It seems certain that in the near future cyclophosphamide-thalidomide-dexamethasone, with an attenuated dose of dexamethasone (CTDa), and melphalan-prednisone-lenalidomide (MPR) will also be proved superior to MP, thus providing four therapeutic options in this patient group. These options could lead to more personalized treatment approaches, based on patient comorbidities, as the three novel agents have somewhat different toxicity profiles. MP would be appropriate for only a minority of patients with poor performance status and/or significant comorbidities. Questions regarding the relative efficacy of different melphalan-based regimens or melphalan-based regimens versus dexamethasone-based regimens with low-dose dexamethasone will require further trials. Additionally, the important issue of maintenance treatment needs to be investigated. These new and emerging therapies provide multiple effective treatment options for MM patients and greatly enhanced treatment strategies for clinicians, all offering promise that has been sorely lacking over the past four decades.

Treatment of relapsed/refractory multiple myeloma

The introduction of several novel and active treatments and improvements in supportive care of myeloma patients has resulted in a prolongation of the survival of these patients. However, myeloma remains an incurable disease and almost all patients will relapse. Effective management of the relapsing/refractory disease incorporates several different strategies, depending on prior treatments, responses, and duration of responses, as well as residual toxicity, age, and physical condition. High-dose dexamethasone still has a role in the management of disease complications such as cytopenias, renal impairment, or spinal cord compression until another agent is added. High-dose therapy may be considered for selected patients who have a long-term treatment-free interval after their first transplantation. Allogeneic transplantation is limited to selected young patients, preferably with an HLA-matched donor. However, the backbone of current strategies for the management of relapsed/refractory myeloma includes the novel agents thalidomide, bortezomib, and lenalidomide. These agents, either with dexamethasone or in combination with chemotherapy, have shown significant activity both in relapsed and in refractory patients. Based on the results of phase III trials, lenalidomide and bortezomib have increased the post-relapse survival and are active in patients who have received prior novel agents; lenalidomide is active in thalidomide-pretreated or bortezomib-pretreated patients and bortezomib alone or in combination with chemotherapy is active in thalidomide/lenalidomide-pretreated patients. Combinations of novel agents show synergistic activity and may overcome drug resistance. Finally, special consideration is needed for the management of patients with renal impairment or other poor prognostic features.

Curcumin circumvents chemoresistance in vitro and potentiates the effect of thalidomide and bortezomib against human multiple myeloma in nude mice model

Curcumin (diferuloylmethane), a yellow pigment in turmeric, has been shown to inhibit the activation of nuclear factor-kappaB (NF-kappaB), a transcription factor closely linked to chemoresistance in multiple myeloma cells. Whether curcumin can overcome chemoresistance and enhance the activity of thalidomide and bortezomib, used to treat patients with multiple myeloma, was investigated in vitro and in xenograft model in nude mice. Our results show that curcumin inhibited the proliferation of human multiple myeloma cells regardless of their sensitivity to dexamethasone, doxorubicin, or melphalan. Curcumin also potentiated the apoptotic effects of thalidomide and bortezomib by down-regulating the constitutive activation of NF-kappaB and Akt, and this correlated with the suppression of NF-kappaB-regulated gene products, including cyclin D1, Bcl-xL, Bcl-2, TRAF1, cIAP-1, XIAP, survivin, and vascular endothelial growth factor. Furthermore, in a nude mice model, we found that curcumin potentiated the antitumor effects of bortezomib (P<0.001, vehicle versus bortezomib+curcumin; P<0.001, bortezomib versus bortezomib+curcumin), and this correlated with suppression of Ki-67 (P<0.001 versus control), CD31 (P<0.001 versus vehicle), and vascular endothelial growth factor (P<0.001 versus vehicle) expression. Collectively, our results suggest that curcumin overcomes chemoresistance and sensitizes multiple myeloma cells to thalidomide and bortezomib by down-regulating NF-kappaB and NF-kappaB-regulated gene products.

Challenging issues in molecular-targeted therapy

There are variety of anticancer treatments including chemotherapeutic drugs, which are known to induce cell growth arrest and apoptosis through DNA damage and cytoskeleton toxicity. Meanwhile, histone deacetylase (HDAC) inhibitors could apply their antitumor activity through chromatin remodeling and gene expression modulation that affect the cell cycle and survival pathways. This paper proposes an anticancer three-drug compound and discusses several challenging issues in relation to designing multidrug compounds that could possibly lead to molecular-targeted therapies.

Bortezomib, ascorbic acid and melphalan (BAM) therapy for patients with newly diagnosed multiple myeloma: an effective and well-tolerated frontline regimen

BACKGROUND

We conducted a single-arm, multicentre phase 2 study to evaluate bortezomib, ascorbic acid and melphalan (BAM) for patients with newly diagnosed multiple myeloma (MM).

METHODS

Induction consisted of up to eight 28-d cycles of bortezomib 1.0 mg/m(2) on days 1, 4, 8 and 11, plus oral ascorbic acid 1 g and oral melphalan 0.1 mg/kg on days 1-4, followed by maintenance bortezomib 1.3 mg/m(2) every 2 wk until progression.

RESULTS

Among 35 patients enrolled (median age 70 yr), responses occurred in 23/31 evaluable patients (74%) including five (16%) complete, three (10%) very good partial, six (19%) partial and nine (29%) minimal responses. Six patients (19%) had stable disease. Thus, disease control was achieved in 29 (94%) patients. Median times to first and best responses were 2 and 3 months (ranges 1-5 and 1-7), respectively. Median time to progression was 19 months and median overall survival has not been reached (range 2-23+ months). Grade 3 and 4 adverse events occurred in 17 and 5 patients, respectively; the most common were neutropenia, neuropathy and thrombocytopenia.

CONCLUSIONS

BAM is an efficacious, well-tolerated and steroid- and immunomodulatory drug (IMiD)-free frontline treatment regimen for MM patients.

The potential of proteasome inhibitors in cancer therapy

BACKGROUND

The ubiquitin-proteasome system has become a promising novel molecular target in cancer due to its critical role in cellular protein degradation, its interaction with cell cycle and apoptosis regulation and its unique mechanism of action.

OBJECTIVE

This review focuses both on preclinical results and on data from clinical trials with proteasome inhibitors in cancer.

METHODS

Results in hematological malignancies and solid tumors were included, and important data presented in abstract form were considered in this review.

RESULTS/CONCLUSION

Bortezomib as first-in-class proteasome inhibitor has proven to be highly effective in some hematological malignancies, overcomes conventional chemoresistance, directly induces cell cycle arrest and apoptosis, and also targets the tumor microenvironment. It has been granted approval by the FDA for relapsed multiple myeloma, and recently for relapsed mantle cell lymphoma. Combination chemotherapy regimens have been developed providing high remission rates and remission quality in frontline treatment or in the relapsed setting in multiple myeloma. The combination of proteasome inhibition with novel targeted therapies is an emerging field in oncology. Moreover, novel proteasome inhibitors, such as NPI-0052 and carfilzomib, have been developed. This review summarizes our knowledge of the ubiquitin-proteasome system and recent data from cancer clinical trials.

The combination of bortezomib, melphalan, dexamethasone and intermittent thalidomide is an effective regimen for relapsed/refractory myeloma and is associated with improvement of abnormal bone metabolism and angiogenesis

This phase 2 study aimed to determine the efficacy and safety of the combination of bortezomib, melphalan, dexamethasone and intermittent thalidomide (VMDT) and its effect on bone remodeling and angiogenesis in relapsed/refractory myeloma. Bortezomib (1.0 mg/m(2)) was given on days 1, 4, 8, 11, oral melphalan (0.15 mg/kg) on days 1-4, whereas thalidomide (100 mg per day) and dexamethasone (12 mg/m(2)) were administered on days 1-4 and 17-20 of a 28-day cycle, for four cycles. Patients without disease progression continued for up to eight cycles. VMDT effect on bone remodeling was evaluated by measuring osteoclast regulators (soluble receptor activator of nuclear factor-kappa B ligand/osteoprotegerin ratio, osteopontin, macrophage inflammatory protein-1alpha), dickkopf-1 protein, bone resorption and formation markers, whereas its effect on angiogenesis was assessed by measuring serum vascular endothelial growth factor, angiogenin, angiopoietin-2 and basic fibroblast growth factor, after four cycles and at the study end. A total of 62 patients were enrolled. The overall response rate was 66%: CR 13%, vgPR 27% and PR 26%. Median time to response was 35 days and median time to progression was 9.3 months. Common adverse events included cytopenias, peripheral neuropathy and infections. No patient experienced deep-vein thrombosis. VMDT reduced angiogenic cytokines, osteoclast regulators, dickkopf-1 and bone resorption. We conclude that VMDT with intermittent thalidomide is an active and well-tolerated regimen for relapsed/refractory myeloma, affecting abnormal bone remodeling and angiogenesis.

Bortezomib plus melphalan and prednisone for initial treatment of multiple myeloma

BACKGROUND

The standard treatment for patients with multiple myeloma who are not candidates for high-dose therapy is melphalan and prednisone. This phase 3 study compared the use of melphalan and prednisone with or without bortezomib in previously untreated patients with multiple myeloma who were ineligible for high-dose therapy.

METHODS

We randomly assigned 682 patients to receive nine 6-week cycles of melphalan (at a dose of 9 mg per square meter of body-surface area) and prednisone (at a dose of 60 mg per square meter) on days 1 to 4, either alone or with bortezomib (at a dose of 1.3 mg per square meter) on days 1, 4, 8, 11, 22, 25, 29, and 32 during cycles 1 to 4 and on days 1, 8, 22, and 29 during cycles 5 to 9. The primary end point was the time to disease progression.

RESULTS

The time to progression among patients receiving bortezomib plus melphalan-prednisone (bortezomib group) was 24.0 months, as compared with 16.6 months among those receiving melphalan-prednisone alone (control group) (hazard ratio for the bortezomib group, 0.48; P<0.001). The proportions of patients with a partial response or better were 71% in the bortezomib group and 35% in the control group; complete-response rates were 30% and 4%, respectively (P<0.001). The median duration of the response was 19.9 months in the bortezomib group and 13.1 months in the control group. The hazard ratio for overall survival was 0.61 for the bortezomib group (P=0.008). Adverse events were consistent with established profiles of toxic events associated with bortezomib and melphalan-prednisone. Grade 3 events occurred in a higher proportion of patients in the bortezomib group than in the control group (53% vs. 44%, P=0.02), but there were no significant differences in grade 4 events (28% and 27%, respectively) or treatment-related deaths (1% and 2%).

CONCLUSIONS

Bortezomib plus melphalan-prednisone was superior to melphalan-prednisone alone in patients with newly diagnosed myeloma who were ineligible for high-dose therapy. (ClinicalTrials.gov number, NCT00111319.)

Phase I-II trial of bortezomib plus oral cyclophosphamide and prednisone in relapsed and refractory multiple myeloma

PURPOSE

The combination of oral weekly cyclophosphamide and alternate day prednisone is a convenient regimen for relapsed/refractory multiple myeloma (MM), and we sought to improve its efficacy by adding bortezomib, a proteasome inhibitor with proven antimyeloma activity.

PATIENTS AND METHODS

We conducted a phase I-II trial evaluating six dose levels to define the maximum tolerated dose (MTD) of this combination in relapsed/refractory MM. An additional 10 patients were evaluated at the highest dose level reached.

RESULTS

Thirty-seven patients were treated on this study. The MTD was not defined. Both of the highest dose levels of bortezomib tested (1.3 mg/m(2) on days 1, 4, 8, and 11 and 1.5 mg/m(2) on days 1, 8, and 15, each on a 28-day cycle) could be safely given with cyclophosphamide 300 mg/m(2) per week and prednisone. At these dose levels, the overall response rate was 95% (complete responses [CR] plus partial response plus minimal response), with CR observed in more than 50% of patients. The weekly bortezomib regimen resulted in fewer instances of grade 3 thrombocytopenia and grade 1 to 2 peripheral neuropathy; the 1-year progression-free and overall survival probabilities with this dose level were 83% (95% CI, 73% to 96%) and 100%, respectively.

CONCLUSION

Weekly bortezomib 1.5 mg/m(2) plus oral cyclophosphamide and prednisone produces an unprecedented response rate and encouraging 1-year survival in relapsed/refractory patients with MM. Further evaluation of this promising regimen is warranted both in relapsed and newly diagnosed disease.

NF-kappaB in the pathogenesis and treatment of multiple myeloma

PURPOSE OF REVIEW

This review aims to summarize recent advances in the mechanisms through which the activation of the transcription factor NF-kappaB contributes to the pathogenesis of multiple myeloma.

RECENT FINDINGS

This transcription factor regulates expression of numerous genes involved in multiple myeloma pathogenesis, including growth, survival, immortalization, angiogenesis and metastasis. Recently, mutations of NF-kappaB signaling molecules have been identified in multiple myeloma cells. In addition, interactions between multiple myeloma cells and the bone marrow environment play critical roles in NF-kappaB activation as well as in multiple myeloma pathogenesis. Moreover, several drugs that are effective against multiple myeloma, including bortezomib, thalidomide, lenalidomide and arsenic trioxide, have been found to block activation of NF-kappaB. The combination of conventional chemotherapeutic drugs and those that block NF-kappaB activation has now proven to be effective in the treatment of multiple myeloma.

SUMMARY

Recent studies further underscore the critical role of NF-kappaB in multiple myeloma pathogenesis and have provided the rationale for multiple myeloma therapy with NF-kappaB-specific inhibitors combined with conventional chemotherapeutic drugs.

Proteasome inhibitors in cancer therapy: lessons from the first decade

The ubiquitin-proteasome pathway is involved in intracellular protein turnover, and its function is crucial to cellular homeostasis. First synthesized as probes of proteolytic processes, proteasome inhibitors began to be thought of as potential drug candidates when they were found to induce programmed cell death preferentially in transformed cells. They made their first leap into the clinic to be tested as therapeutic agents 10 years ago, and since then, great strides have been made in defining their mechanisms of action, their clinical efficacy and toxicity, and some of their limitations in the form of resistance pathways. Validation of the ubiquitin-proteasome pathway as a target for cancer therapy has come in the form of approvals of the first such inhibitor, bortezomib, for relapsed/refractory multiple myeloma and mantle cell lymphoma, for which this agent has become a standard of care. Lessons learned from this first-in-class agent are now being applied to the development of a new generation of proteasome inhibitors that hold the promise of efficacy in bortezomib-resistant disease and possibly in a broader spectrum of diseases. This saga provides a salient example of the promise of translational medicine and a paradigm by which other agents may be successfully brought from the bench to the bedside.

Differential radiation sensitization of human cervical cancer cell lines by the proteasome inhibitor velcade (bortezomib, PS-341)

PURPOSE/OBJECTIVE(S)

Cervical cancer is one of the deadliest cancers in women with a death toll of 230,000 worldwide each year, nearly 80% in developing countries. Radiotherapy (RT) is a major treatment modality for advanced cervical cancer but the local relapse rate is 30-44% in patients treated with RT alone and 19-25% in patients treated with concurrent chemoradiotherapy. Previous studies have shown that the transcription factor NF-kappaB is constitutively expressed in human cervical squamous cell carcinomas. NF-kappaB activation also contributes to the resistance of cervical cancer cells to apoptosis induced by chemotherapeutic agents and radiation. Therefore, inhibition of NF-kappaB in tumor cells may render them more sensitive to chemo/radiation therapies. The objective of this study is to investigate the potential of radiosensitization of NF-kappaB inhibition by Velcade in human cervical cancer cell lines.

MATERIALS AND METHODS

We used the human cervical cancer cell lines HeLa and SiHa. Both are highly radioresistant and chemoresistant as compared to other cervical cancer cell lines. These cells had been treated with Velcade before they were irradiated with different doses of ionizing radiation. MTT metabolic assays and clonogenic cell survival assays were performed to evaluate the effects of Velcade on radiation resistance.

RESULTS

Inhibition of NF-kappaB by Velcade alone decreased metabolic potential (MTT) and clonogenic survival in SiHa, but not in HeLa cells. Furthermore, pre-treatment of SiHa, but not HeLa cells with Velcade enhanced radiation sensitivity.

CONCLUSIONS

Inhibition of NF-kappaB by the proteasome inhibitor Velcade enhances radiosensitivity of certain human cervical carcinoma cancer cells in vitro. These results raise the possibility that inhibition of NF-kappaB will result in radiosensitization only in those tumor cells which are more dependent on NF-kappaB for their metabolism and survival, however, the radiosensitivity of "NF-kappaB independent" cells are not likely influenced by it.

[New therapeutic strategies for multiple myeloma. Efficacy and cost-effectiveness analyses]

The objective of the present article is the review of the most important therapeutic innovations in the treatment of multiple myeloma in terms of efficacy and cost-effectiveness. Besides autologous transplant with peripheral-blood stem-cell, thalidomide establishes as one of the most powerful therapeutic tools in induction and maintenance treatment and together with lenalidomide and bortezomib as therapy for relapsing/refractory multiple myeloma. Considering, the last named situation thalidomide can be an adequate therapeutical option in combination with dexamethasone. Under a strictly pharmacoeconomic point of view, lenalidomide and bortezomib seem to be additional alternatives in patients previously treated with thalidomide.

Position statement on the use of bortezomib in multiple myeloma

Bortezomib (Velcade) is a boron containing molecule which reversibly inhibits the proteasome, an intracellular organelle which is central to the breakdown of ubiquinated proteins and consequently crucial for normal cellular homeostasis. Phase II clinical trials demonstrate it is effective for the treatment of relapsed refractory myeloma, and a phase III trial comparing bortezomib to dexamethasone in second/third line treatment showed superiority in progression free and overall survival. It is administered intravenously in the outpatient setting on days 1, 4, 8 and 11 of a 21-day cycle and regular monitoring for side effects is essential. It is currently approved for the treatment of multiple myeloma patients who have received at least one prior therapy and who have already undergone or are unsuitable for transplantation. Given the strength of this data the UK Myeloma Forum and British Committee for Standards in Haematology believe that bortezomib should be available for prescription by UK haematologists according to its licensed indication in patients with relapsed myeloma.